CN1034668C - Lubricant for central spindle for hot-rolling steel tube - Google Patents

Abstract

The present invention relates to a lubricant suitable for a mandril of a hot rolled steel pipe in high temperature environment, which is compounded from No. 1 metaphosphate containing metallic ions of sodium, potassium and ammonium, No. 2 polyphosphate containing metallic ions of sodium, potassium and ammonium, No. 3 trisodium phosphate and water. The lubricant has four composition forms which are respectively formed from No. 1, No. 2 and No. 3 phosphate materials and water, No. 1 and No. 2 phosphate materials and water, No. 1 and No. 3 phosphate materials and water, and the mixture of No. 1 phosphate material and water, which is used as the lubricant of a mandril of a hot rolled steel pipe. The lubricant has the advantages of innocuity, no corrosion, no pollution and good lubrication effect.

Description

The lubricant of central spindle for hot-rolling steel tube

The present invention relates to be used for the lubricant of metal tube rolling mill mandrel, especially for the lubricant of central spindle for hot-rolling steel tube.

In modern steel pipe's production, the mandrel outreach tool that is absolutely necessary, and lubricated between mandrel and the hair steel pipe is vital.In the tube mill group, mandrel is smeared the lubricant of coideal, can reduce machine utilization, improves the work-ing life of mandrel, helps mao steel pipe simultaneously and obtains a good surface, inside, and make between mao steel pipe and the mandrel easily the pine axle and take off axle.

At present, the lubricant for mandrel of hot finished steel pipe unit use both at home and abroad mainly contains two classes, and a class is the graphite mould lubricant, and a class is a molybdenum disulfide lubricant.

The graphite mould lubricant is main component with graphite, European patent EP 357508 disclosed a kind of lubricants for example, the acid polysalt that is accounted for weight ratio 1～5% by thin Graphite Powder 99, water-fast synthetic resin, rock asphalt powder, interpolation is formed, and the metal ion of salt is Na, K, Ca, Mg, NH ₄, the synthetic resin weight percent is 15～40%, can be polyacrylic acid, polyvinyl acetate (PVA), polystyrene, polyethylene epoxy resin.When the mandrel surface temperature is in 100～400 ℃ of scopes, the graphite mould lubricant can form composite lubricating film on the mandrel surface, whenever roll once in the production, mandrel after taking off axle must be cooled in the flowing cold water groove about 100 ℃, recirculation is used, thereby the temperature of mandrel is lower, can rely on automatic spray apparatus to make graphite nationality tackiness agent be attached to the mandrel surface effectively.But the mandrel that this lubricant is not suitable for the high temperature hot finished steel pipe more than 500 ℃ uses.For example, when using on push bench, the mandrel preheating temperature is in 500～550 ℃ of scopes, and rollingly take off that a back temperature is taller to reach 600～700 ℃, this moment graphitization type lubricant, because of graphite conducts heat fast, there is ferric oxide on the mandrel surface in addition, just is difficult to coat mandrel, and lubrication is influenced; Iron scale falls into oiling system, makes the recycle pump rapid wearing and can not normally use; Shutdown period also must in time be removed the graphite that gathers in pipeline and the pump, in order to avoid blocking pipe.Though smokeless, nontoxic, the no corrosive nature of graphite mould lubricant because of it splashes down, can be polluted the scene during tube rolling.

Molybdenum disulfide lubricant is that molybdenumdisulphide and grease are mixed, must be applied on the mandrel by hand-operated tools during use, because its is mobile poor, be difficult to operate, during the high temperature hot rolling on plug poor adherence, easily oxidation, grease is smoldered easily, is burnt and splash as tackiness agent, when temperature is hanged down, though can be attached on the mandrel, but rolling totally unfavorable to push pipe, easily cause and roll card.The reliable Applicable temperature scope of molybdenum disulfide lubricant is at-20 ℃～180 ℃, using under the high temperature more than 200 ℃, particularly the head wearing and tearing are very serious on the mandrel surface, be to cause the steel pipe even one of the main reasons of inhomogeneity of wall thickness along its length, thereby the number of times that effectively utilizes of mandrel is reduced.

The objective of the invention is, overcome the weak point of above-mentioned existing lubricant for mandrel, invent a kind ofly in hot environment, be easy to apply, the lubricant of good, the no burn into nontoxicity of lubricity, free of contamination central spindle for hot-rolling steel tube.

Technical essential of the present invention is, the high temperature modification lubricant be three kinds of phosphoric acid salt with the different components and the mixture of water, by its component characteristics 4 kinds of forms are arranged.

1. lubricant is metal ion sodium, potassium, ammonium metaphosphate-I number, poly-phosphate-II number, tertiary sodium phosphate (Na of metal ion sodium, potassium, ammonium ₃PO ₄12H ₂O)-and the mixture of III number and water, its components by weight scope is I number: II number: III number: water=(0.14～0.22): (0.05～0.19): (0.03～0.06): 1.

2. lubricant is metal ion sodium, potassium, ammonium metaphosphate-I number, metal ion sodium, potassium, ammonium the poly-phosphate-II number mixture with water, and its components by weight scope is I number: II number: water=(0.14～0.25): (0.05～0.25): 1.

3. lubricant is metaphosphate-I number, a phosphoric acid of metal ion sodium, potassium, ammonium

Trisodium-III number the mixture with water, its components by weight scope is I number: III number: water=(0.14～0.67): (0.01～0.05): 1.

Metaphosphate-the I of metal ion sodium, potassium, ammonium number with the mixture of water lubricant as central spindle for hot-rolling steel tube, its components by weight scope is I number: water=10.18～0.821: 1.

In above-mentioned three kinds of phosphoric acid salt, I number preferred material is six inclined to one side and above sodium-metaphosphate (NaPO ₃) _N＞6, six inclined to one side and above potassium metaphosphate (KPO ₃) _N＞6, ammonium metaphosphate (NH ₄PO ₃); II number preferred material is trisodium phosphate Na ₄P ₂O ₇, potassium pyrophosphate K ₄P ₂O ₇, trimerization and above sodium polyphosphate Na thereof _N+2P _nO _3n+1(n＞3), trimerization and above Rapisol K thereof _N+2P _nO _3n+1(n＞3), ammonium polyphosphate (NH ₄) _N+2P _nO _3n+1Because the sodium salt source is wide, output is high, price is low, how to make the lubricant raw material with metaphosphate, the poly-phosphate of metal ion sodium in production practice.

3 kinds of phosphoric acid salt of the present invention mix the lubricant that constitutes with water with different components, in aforementioned 4 kinds of composition forms and compositional range thereof, all has following effect: good fluidity, do not precipitate, be easy to coat 100～800 ℃ of pyritous mandrel surfaces, can realize applying automatic operation, not can with mandrel generation chemical reaction, form thin film on mandrel surface, satisfy lubricating requirement, prevent the metal adhesion, when temperature more than 800 ℃ the time, show activation performance, meet the push pipe requirement, be difficult for rolling card, when lubricant is in melted state, form the friction condition of semi liquid state, and under the situation of film breaks, the one deck of covering once more liquid phase lubricant film that can be very fast, thus frictional coefficient between mandrel and the hair steel pipe reduced, finally reduced the total pressure of metal pair roll.

Lubricant measure of merit one of the present invention, as table 1, table 2 and shown in Figure 1, when table 1, table 2 are respectively rolling φ 102 * 4mm steel pipe, be coated with push bench motor 1D, the 2D current average test chart of molybdenum disulfide lubricant and lubricant of the present invention, Fig. 1 is for being coated with molybdenum disulfide lubricant a respectively, lubricant b of the present invention, current waveform figure by the push bench motor 1D of electric current self-registering instrument record, from table 1, table 2 and Fig. 1 as can be seen, under the same conditions, be coated with lubricant of the present invention, the push bench energy consumption of electrical machinery reduces by 15～20%.

Lubricant measure of merit two of the present invention, as shown in table 3, table 3 is for using molybdenum disulfide lubricant and lubricant of the present invention, and under identical tube rolling mill and the same terms, hair steel pipe length is relatively.As can be seen from Table 3, use lubricant of the present invention, it is 3.1% that the hair steel pipe extends increment rate.

Lubricant measure of merit three of the present invention, as shown in Figure 2, Fig. 2 is for using oildag c, molybdenum disulfide lubricant a, lubricant b of the present invention respectively, mandrel (14 every group) tube rolling with the same quantity of same rolling frequency (2.5 of per minutes), the tube rolling temperature is identical, measures the temperature variation after three mandrels take off axle in half an hour.As can be seen from Figure 2, temperature is minimum behind the mandrel tube rolling of use lubricant of the present invention, illustrate that lubricant heat-insulating property of the present invention is good, it is slow to conduct heat, lubricity is good, and when supplied materials hair steel pipe temperature is low slightly (as 1020 ℃), push pipe can not roll card, alleviate labor strength, prolong push bench work-ing life.

Lubricant of the present invention can not only reduce machine utilization, delay the wearing and tearing of high Kind of Warm Rolled Pipe mandrel, and nontoxic, no burn into do not have bad smell, pollution-free, can be widely used in push pipe unit and continuous rolling-tube unit, Pilger is pricked the lubricated of pipe unit and other hot-work unit.

Non-limiting examples of the present invention: in aforementioned 4 kinds of composition forms and components by weight scope thereof, choose arbitrarily a kind of form and one group components by weight scope in phosphoric acid salt and water, after stirring with mechanical stirring device, lubricant of the present invention.

4 kinds of composition forms of the present invention and components by weight preferred embodiment thereof:

1. Sodium hexametaphosphate 99 (hexa metaphosphoric acid potassium, Hexamethylphosphoric acid triamide): trisodium phosphate (potassium pyrophosphate) or tripoly phosphate sodium STPP (Potassium tripolyphosphate, ammonium polyphosphate): tertiary sodium phosphate: water=0.18: 0.10: 0.04: 1 or=0.22: 0.14: 0.03: 1 or=0.14: 0.19: 0.03: 1

2. Sodium hexametaphosphate 99 (hexa metaphosphoric acid potassium, Hexamethylphosphoric acid triamide): trisodium phosphate (potassium pyrophosphate) or tripoly phosphate sodium STPP (Potassium tripolyphosphate, ammonium polyphosphate): water=0.18: 0.06: 1 or=0.25: 0.05: 1

3. Sodium hexametaphosphate 99 (hexa metaphosphoric acid potassium, Hexamethylphosphoric acid triamide): tertiary sodium phosphate: water=0.18: 0.05: 1 or=0.54: 0.02: 1

4. Sodium hexametaphosphate 99 (hexa metaphosphoric acid potassium, Hexamethylphosphoric acid triamide): water=0.22: 1 or=0.43: 1

Table 1 is coated with Molykote push-bench current of electric

Mean value

Sequence number	Temperature (℃)	Current value (A)
				1D	2D
		1	1060			2482	2315
2	1064			2462	2296
		3	1067			2435	2302
4	1072			2355	2291
		5	1075			2370	2306
6	1081			2452	2140
		7	1085			2435	2128
8	1088			2406	2268
		9	1091			2362	2136
10	1110			2265	2128

$\stackrel{\‾}{I}=\frac{1}{10}\left[\mathrm{\Σ}(I_{101}+I_{201})\right]=4633A$

Table 2 is coated with the multiple phosphate mixt lubricant of the present invention push-bench

Current of electric mean value

Sequence number	Temperature (℃)	Current value (A)
				1D	2D
		1	1062			2010	1945
2	1066			2032	1943
		3	1069			1995	1934
4	1074			1982	1885
		5	1078			1988	1872
6	1083			1920	1850
		7	1087			1925	1840
8	1092			1935	1825
		9	1095			1895	1840
10	1106			1865	1832

$\stackrel{\‾}{I}=\frac{1}{10}\left[\mathrm{\Σ}(I_{101}+I_{201})\right]=3832A$

Table 3 hollow billet Length Ratio is (m)

The lubricant kind	1	2	3	4	5	6	7
								Molybdenum bisuphide	11.30	11.35	11.15	11.35	11.10	11.32	11.12
Mixture of the present invention	11.60	11.65	11.68	11.50	11.65	11.60	11.62

The lubricity kind	8	9	10	11	12	Average length
							Molybdenum bisuphide	11.25	11.15	11.22	11.20	11.50	11.25
Mixture of the present invention	11.55	11.65	11.50	11.70	11.58	11.60

Δl＝11.60－11.25＝0.35m

Claims (5)

1, a kind of lubricant of central spindle for hot-rolling steel tube is characterized in that this lubricant is the mixture of Sodium hexametaphosphate 99 and water, and its components by weight scope is: Sodium hexametaphosphate 99: water=(0.14--0.82): 1.

2, lubricant according to claim 1 is characterized in that can also comprising tripoly phosphate sodium STPP in the component, and its components by weight scope is: Sodium hexametaphosphate 99: tripoly phosphate sodium STPP: water=(0.14--0.25): (0.05--0.25): 1.

3, lubricant according to claim 1 is characterized in that can also comprising tertiary sodium phosphate in the component, and its components by weight scope is: Sodium hexametaphosphate 99: tertiary sodium phosphate: water=(.014--0.67): (0.01--0.05): 1.

4, lubricant according to claim 2, it is characterized in that can also comprising tertiary sodium phosphate in the component that its components by weight scope is: Sodium hexametaphosphate 99: tripoly phosphate sodium STPP: tertiary sodium phosphate: water=(0.14--0.22): (0.05--0.19): (0.03--0.06): 1.

5,, it is characterized in that the tripoly phosphate sodium STPP in the component can be substituted by trisodium phosphate according to claim 2 or 4 described lubricants.

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